Existing commercially available spring-return, plunger-style locking/indexing pins suitable for use as fluid connection lock pins are subject to a number of significant disadvantages. Among other things, currently available spring-return, plunger-style locking/indexing pins are typically permanently sealed and hence not user serviceable. In addition, some of these locking/indexing pins use knob-style grips made of plastic, which are unable to withstand the rigors of some operating environments, such as those encountered during railroad service. Those commercially available locking/indexing pins that do use knob-style grips made from metal disadvantageously shroud the internal mechanism.
In addition, existing commercially available spring-return, plunger-style locking/indexing pins are prone to retaining rain water and other materials inside the locking pin body. In cold weather operations, retained water results in ice build-up and renders the locking/indexing pin inoperable. Furthermore, the closed design neither allows the operator see any ice build-up or other material accumulations to verify operation nor drainage from the device interior.